Method of forming lath panels



I Feb. 10, 1931. BUTTRESS I 1,791,792

METHOD OF FORMING LATH PANELS Filed Nov. 13; 1928 Patented'Feb. 10, 1931 UNITED STATES PATENT OFFICE-Y GEORGE A. BUTTRESS, DE LOS ANGELES, CALIFORNIA, ASSIGNOR TO E. AND HOLDING COMPANY, OF LOS ANGELES, CALIFORNIA, A CORPORATION OF CALIFORNIA METHOD OF FORMING LA'IH PANELS I Application filed November 13, 1928. Sei-ial No. 319,172.

This invention relates to a fabricated lath panel and particularly pertains to a lath board of the character embodying a series of spaced parallel paper covered composition ribsof the character disclosed in my copending application for United States Letters Patent Serial No. 236,081, filed November 28, 1927, and referred to in copending applications filed November 23, 1926, Serial No. 150,250, and filed November 23, 1927, Serial No. 235,214, and also referred to in an application filed coincidently herewith.

An object of this invention is to provide a sheet lath of the above character and method of making same in which the series of parallel composition ribs, preferably formed of a hardened plastic material, are spaced apart and carried upon a backing sheet with their outer faces and contiguous edges covered by a facing sheet in such manner as to form channels between adjacent ribs and with the bottom walls of the channels and the longitudinal margins of the sheet of the lath formed by the combined thickness of the backing sheet and facing sheet, whereby the sheet will be formed with flexible marginal flaps and the bottom walls of the channels will be rendered somewhat flexible throughout their transverse width.

Another object is to provide a means for effecting positive connection between the over-lapping marginal flap portions of the sheet lath whereby the facing and backing sheets will be secured together a ainst being readily separated along the flaps oth during the operation of fabricating the lath and after completion thereof.

Another object is to provide an effective method of forming the lath ribs and the channels therebetween of dove-tail cross.section and in so doing render the composition of which the lathribs are formed highly compact, and whereby such ribs when dry and hard will be rendered strong and greatly resistant to bending strains.

filled with a plastic composition to form thesheet with slats or ribs;

Fig. 4 is a View in cross section showing the manner in which a backing sheet is applied and secured to the facing sheet;

Fig. 5 is a diagram in section illustrating the initial step of forming the ribs and the channels therebetween of dove-tail cross section;

Fig. 6 is a diagram illustrating the final operation of forming the ribs and channels therebetween of dove-tail cross section.

Referring to the drawing more specifically, A indicates the corrugated facing sheet, B the backing sheet and C the composition ribs interposed between the sheets A and B. The

facing sheet A is initially formed with parallel corrugations of substantially rectangular cross section as shown in Fig. 2, there being composition-receiving corrugations 7 on one side of the sheet between which extend. corrugations 8 opening to the other side of the sheet to form vacant channels. The corrugations 7 and 8 are separated by side walls 9 connected together by walls. 10 forming the bottom Walls of the corrugation ,7, and by walls 11 forming the bottom walls of the corrugations or channels .8. The end or marginal corrugations 7 have outer side walls 9 from which project marginal walls 11 to form marginal flaps D along the longitudinal edges of a panel or sheet of the finished lath. The composition C, preferably embodying plaster of Paris and other suitable ingredients mixed with water, is placed in the corrugations 7 while in a soft wet condition to fill the corrugations flush with the outer surface of the wall 1111 as shown in Fig. 3, whereupon the backing sheet B is applied to extend over the'ribs G and over the walls 1111 in intimate contact therewith as shown in Fig. 4.

The longitudinal margins of the sheets A and B are interconnected by disrupting the material of the sheet contiguous to the edges thereof and causing such disrupted portions of the two sheets to become entangled or termingled in such manner as, to interlock and thereby fasten the sheets together. This may be accomplished by inserting a sharp tapered implement through the over-lapping sheets so as to rupture-the material and form tangs or burrs that will project from the margin of the punch hole in the sheet B into and through the punch hole in the sheet A as indicated at, 12 in Fig. 5. These punchings are formed at suitable intervals apart contiguous to the edge of the sheet throughout the length thereof. After these disruptions are formed they are firmly pressed together in any suitable manner as by rolling the marginal portions of the sheet or subjecting them to a squeezing action.

After the sheet lath is thus formed, the rectangular corrugations are converted into corrugations of dovetail cross section while the plastic composition is soft and a he same time the composition ribs are compressed to remove excess water and render the composition more compact and thereby imparting greater strength and stability thereto in the finished product.

In carrying out the present invention, this dove-tailing action may be accomplished in any desired manner, but-is here shown as effected by means of a pair of blades and plates 13 and 14 which are inserted in the channels formed by the-corrugations 8 to seat on the contiguous face of the walls 9 as shown in Fig. 5, whereupon the inner edge portions of the plates are spread apart by-means of a wedge 15 so as to press the walls 9 into the plastic composition as shown in Fig. 6; this operation being effected in such manner that the side walls 9 will be fore-shortened and the walls 11 lengthened. During this operation the sheet or. panel is subjected to pressure throughout as by impressing it between the members 16 and 17 of a press, as shown in Fig. 6, whereby the composition ribs are compressed and rendered shallower. During this operation, which is: effected while the composition is soft and wet, each of the ribs will be subjected to pressure from all four sides thereof and excess water in the composition will be squeezed therefrom; portions of the water emerging through the flaps and at the end of the ribs and corrugations. This pressing action brings the backing sheet into intimate contact with the plastic ribs and at the same time the plastic is compressed into intimate contact with the contiguous surface of the corrugated sheet A which because of the natural adhesive quality of the plastic and "the fibrous character of the sheets A and B securely bonds the sheets and plastic ribs together. The pressing ofthe interconnecting burrs on the margins of the sheet may be effected in the one operation of compressing the plastic just described.

,The panel is then out into dimensioned sizes, preferably while the composition is soft and wet, that is; before setting thereof, and is thereafter dried.

The panel thus formed constitutes the finished product and is ready for application and use on drying of the plastic composition which then becomes hard, and by reason of the plastic ribs being compressed and being completely confined within a fibrous shell afforded by the sheets A. and B will be greatly resistant to bending-strains. However, the bottom walls of the channels connecting adjacent ribs being formed bysuperimposed layers of the fibrous sheet will be somewhat I flexible and will thereby permit bending of 95 the lath panels in a direction transversely I of the ribs. The panels being thus flexible in one direction may be applied to either inwardly or outwardly curved surfaces.

The panels thus formed may be of any suitable dimensions being usually formed with ribs of a length such that they. may be applied to beams and studding in the manner common to ordinary lath.

. By forming the lath panels in the manner set forth, less water may be used in the plastic composition in proportion to the other ingredients than is ordinarily em loyed in theproduction of Wall boards an lath panels embodying compositions of this character. This is highly advantageous in that drying of the panels is greatly facilitated and more rapidly effected as the time required for evaporation of the water is considerably reduced.

By interconnecting the marginal portions of the sheets in the manner set forth possibility of separation of the sheets along the edges ofthe flaps is reduced to a minimum.

An important feature of the invention resides in the manner of forming the ribs and channels therbetween of dove-tail cross-section by spreading the side walls of the channels outwardly adjacent to the bottom walls of the channels so that the widths of the bottom walls will be increased by material added thereto from the side walls; this operation obviating stretching of the portion of the corrugated sheet constituting the bottom walls of the channels and thus avoiding rupturing of the corrugated sheet in this operation.

.side walls 9 extending between the ends of the plates and the bottom walls of the channels will be added to such bottom walls. This merging of a portion of the side walls into the bottom walls of the channels is facilitated by co-incidentally spreading the side walls laterally and advancing the bottom walls in the direction of the depths of the channels under the action of the press elements 16 and 17.

Iclaim:

1. The method of forming rib lath panels consisting in providing a sheet of fibrous material with substantially rectangular corrugations, filling the corrugations on one side of the sheet with a soft and wet plastic composition, imposing a flexible fibrous backing sheet over and in direct contact with the corrugated sheet to cover the plastic composition whereby composition ribs of substantially rectangular cross-section are formed with each rib completely enclosed by the fibrous sheet apart from contiguous ribs, then compressing the ribs to compact the composition and at the same time convert the ribs into dove-tail cross section.

2. The method of forming rib lath panels consisting in providing a sheet of fibrous material with substantially rectangular corrugations, filling the corrugations on one sideof the sheet with a soft and wet plastic composition, imposing a flexible fibrous backing sheet over and in direct contact with the corrugated sheet to cover the plastic composition whereby composition ribs of substantially rectangular cross-section are formed with each rib-completely enclosed by the fibrous sheet apart from contiguous ribs, then compressing the ribs to compact the composition and at the same time convert the ribs into dove-tail cross-section, by pressing the side walls of the ribs inwardly while the composition is soft in such manner as to widen the bottom portions of the channels formed between adjacent ribs.

1 3. The method of forming rib lath panels consisting in providing a sheet of fibrous material with substantially rectangular corrugations, filling the corrugations on one side of the sheet with a soft and wet plastic composition, imposing a flexible fibrous backing sheet over and in direct contact with the corrugated sheet to cover the plastic composition whereby composition ribs of substantially rectangular cross-section are formed with each rib completely enclosed bythe fibrous sheet apart from contiguous ribs, then subjecting the ribs-to pressure directed simultaneously to all sides thereof.

sisting in providing a sheet of fibrous mate- I rial withsubstantially rectangular corrugations, filling the corrugations on one side of the sheet with a soft and wet plastic composition, imposing a flexible fibrous backing sheet over and in direct contact with the corrugated sheet to cover the plastic composition, and spreading theside walls of the corrugations between contiguous ribs adjacent the bottom walls thereof to form dovetail spaces between the composition ribs.

5. The method of forming rib lath panels consisting in providing a sheet of fibrous material with substantially rectangular corrugations, filling the corrugations on one side of the sheet wit-h a soft and wet plastic composition, imposing a flexible fibrous backing sheet over and in direct contact with the corrugated sheet to cover the plastic composition whereby composition ribs of substantially rectangular cross-section are formed separately by substantially rectangular-channels, and converting the ribs and channels into dove-tail cross-section by spreading the inner portions of the side walls of the channelsoutwardly and pressing the bottom walls of the channels inwardly whereby portions of the side Walls of the channels will be added to the bottom walls to increase the widths of the latter.

6. The method of forming fabricated panels consisting in interposing a body of soft and wet plastic com osition between two fibrous sheets, bringing the sheets together in direct contact and in overlapping relation at the edges thereof, punching interlocking tangs through the overlapped edges of the sheets and then subjecting the overlapped edges to pressure.

7. The method of forming fabricated panels consisting in providing a corrugated sheet of fibrous material, filling the corrugations on one side of the sheet with a plastic composition, imposing a flexible fibrous backing sheet over and in direct contact with the corrugated sheet to cover the plastic composition, bringing the sheet together in overlapping relation at the edges thereof, punching interlocking tangs through the overlapped edges of the sheets and then subjecting the overlapped edges to pressure.

8. The method of forming fabricated panels consisting in providing a corrugated sheet of fibrous material, filling the corrugations on one side of the sheet with a plastic composition, imposing a flexible fibrous backing sheet over and in direct contact with the corrugated sheet to cover the plastic composition, bringing the sheets together in overlapping relation at the edges thereof, punching portions of the overlapped edges of the 7 and wet plastic composition between two sheets, bringing the sheets together in direct contactand'in overlapping relation at the edges thereof, efiecting positive connection between the overlapped edges of the sheets, and then partially drying) the composition and compacting same by so j ecting the structure to pressure.

In testimony whereof, I have aflixed my signature.

GEORGE A. BUTTRESS. 

